Projection display systems typically include a projector and a projection display screen. The projector may be a three-color liquid crystal display projector that combines polarized light from different liquid crystal displays and emits combined light to form images. The projector can project the images on the display screen for presentation to viewers. The display screen may provide a diffuse surface to improve the image quality seen by viewers.
Projectors capable of emitting polarized light may be most efficient when the directions of polarization vary for the different colored lights that are combined. For instance, light polarized in one direction may be more efficient for reflecting, while light polarized in another direction may be more efficient for transmission. Therefore, the light output from the projector may contain some colored light that is reflected within the projector and is polarized in one direction, and may contain other colored light that only transmits through the projector and is polarized in the other direction.
Projection screens typically include particles held in a transparent medium and a reflective material located behind the particles. Conventional projection screens may reflect substantially all of the incident light, including both the light from the imaging source and the ambient light. The reflection of the ambient light towards the viewers may result in reduced contrast of the image, particularly in areas that receive relatively high levels of ambient light. Such reductions in contrast, however, are generally undesirable.
Improving the projection screen and/or the projector can improve the image quality presented to viewers. Furthermore, improvements to the screen and/or the projector may allow the system to be used in non-conventional settings. For theses and other reasons it is highly desirable to improve projectors and projection screens.